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Abstract:

Data is generated, which can prevent content displayed on a screen from
being accurately replicated. There are provided: an acquiring means that
acquires still image data; a still image data generating means that
generates a predetermined number of items of still image data in which at
least part of pixels of the acquired still image data are masked, and
that varies positions of at least part of pixels of pixels to be masked,
between at least two items of still image data of the predetermined
number of still image data; and a movie data generating means that
generates movie data for which each of the generated still image data is
displayed at a predetermined frame rate.

Claims:

1-13. (canceled)

14. A data-generating device comprising: an acquiring means that acquires
still image data; a still image data generating means that generates a
predetermined number of items of still image data in which at least part
of pixels of the acquired still image data are masked, and that varies
positions of at least part of pixels in pixels to be masked, between at
least two items of still image data of the predetermined number of still
image data; and a movie data generating means that generates movie data
for which each of the generated still image data is displayed at a
predetermined frame rate.

15. The data-generating device according to claim 14, wherein the still
image data generating means sets a rate of pixels to be masked at an
outline portion of an image shown by the acquired still image data to be
greater than a rate of pixels to be masked at other portions.

16. The data-generating device according to claim 14, wherein the still
image data generating means sets a rate of pixels to be masked higher
when a number of items of still image data to generate is greater.

17. The data-generating device according to claim 14, wherein the movie
data generating means comprises a frame rate determining means that
determines a frame rate for display, and the still image data generating
means comprises a generation image number determining means that
determines a number of items of still image data to generate based on the
determined frame rate.

18. The data-generating device according to claim 16, wherein the movie
data generating means comprises a frame rate determining means that
determines a frame rate for display, and the still image data generating
means comprises a generation image number determining means that
determines a number of items of still image data to generate based on the
determined frame rate.

19. The data-generating device according to claim 14, wherein the still
image data generating means varies a rate of pixels to be masked in at
least one of regions divided from an image shown by at least one still
image data of the predetermined number of items of still image data, from
a rate of pixels to be masked in other regions.

20. The data-generating device according to claim 15, wherein the still
image data generating means varies a rate of pixels to be masked in at
least one of regions divided from an image shown by at least one still
image data of the predetermined number of items of still image data, from
a rate of pixels to be masked in other regions.

21. The data-generating device according to claim 16, wherein the still
image data generating means varies a rate of pixels to be masked in at
least one of regions divided from an image shown by at least one still
image data of the predetermined number of items of still image data, from
a rate of pixels to be masked in other regions.

22. The data-generating device according to claim 17, wherein the still
image data generating means varies a rate of pixels to be masked in at
least one of regions divided from an image shown by at least one still
image data of the predetermined number of items of still image data, from
a rate of pixels to be masked in other regions.

23. The data-generating device according to claim 18, wherein the still
image data generating means varies a rate of pixels to be masked in at
least one of regions divided from an image shown by at least one still
image data of the predetermined number of items of still image data, from
a rate of pixels to be masked in other regions.

24. The data-generating device according to claim 14, wherein still image
data is generated in which at least one pixel is not masked among pixels
of matching display positions between the predetermined number of items
of still image data.

25. The data-generating device according to claim 15, wherein still image
data is generated in which at least one pixel is not masked among pixels
of matching display positions between the predetermined number of items
of still image data.

26. The data-generating device according to claim 16, wherein still image
data is generated in which at least one pixel is not masked among pixels
of matching display positions between the predetermined number of items
of still image data.

27. The data-generating device according to claim 17, wherein still image
data is generated in which at least one pixel is not masked among pixels
of matching display positions between the predetermined number of items
of still image data.

28. The data-generating device according to claim 18, wherein still image
data is generated in which at least one pixel is not masked among pixels
of matching display positions between the predetermined number of items
of still image data.

29. The data-generating device according to claim 14, wherein the still
image data generating means generates still image data in which a pixel
to be masked is painted with a color determined as a masking color.

30. The data-generating device according to claim 15, wherein the still
image data generating means generates still image data in which a pixel
to be masked is painted with a color determined as a masking color.

31. The data-generating device according to claim 16, wherein the still
image data generating means generates still image data in which a pixel
to be masked is painted with a color determined as a masking color.

32. The data-generating device according to claim 17, wherein the still
image data generating means generates still image data in which a pixel
to be masked is painted with a color determined as a masking color.

33. The data-generating device according to claim 18, wherein the still
image data generating means generates still image data in which a pixel
to be masked is painted with a color determined as a masking color.

34. The data-generating device according to claim 14, wherein the still
image data generating means uses an intermediate color between a color of
a pixel to be masked and a color of pixels around the pixel as a masking
color.

35. The data-generating device according to claim 15, wherein the still
image data generating means uses an intermediate color between a color of
a pixel to be masked and a color of pixels around the pixel as a masking
color.

36. The data-generating device according to claim 16, wherein the still
image data generating means uses an intermediate color between a color of
a pixel to be masked and a color of pixels around the pixel as a masking
color.

37. The data-generating device according to claim 17, wherein the still
image data generating means uses an intermediate color between a color of
a pixel to be masked and a color of pixels around the pixel as a masking
color.

38. The data-generating device according to claim 18, wherein the still
image data generating means uses an intermediate color between a color of
a pixel to be masked and a color of pixels around the pixel as a masking
color.

39. The data-generating device according to claim 14, wherein the still
image data generating means determines a position of a pixel to be masked
such that a mask pattern of still image data to be generated becomes
irregular.

40. The data-generating device according to claim 14, wherein the
acquiring means comprises: an electronic data acquiring means that
acquires electronic data which can be displayed on a screen of a display
device; and a converting means that converts the acquired electronic data
into still image data.

41. A data-generating method comprising: an acquiring step of acquiring
still image data; a still image data generating step of generating a
predetermined number of items of still image data in which at least part
of pixels of the acquired still image data are masked, and varying
positions of at least part of pixels in pixels to be masked, between at
least two items of still image data of the predetermined number of still
image data; and a movie data generating step of generating movie data for
which each of the generated still image data is displayed at a
predetermined frame rate.

Description:

TECHNICAL FIELD

[0001] The present invention relates to a technical field of preventing
content displayed on a screen from being replicated.

BACKGROUND ART

[0002] Conventionally, screen capture (also referred to as, for example,
"screen shot" or "screen dump") is known of storing content to be
displayed on a screen by display processing of electronic data such as
electronic document or images as still image data. This screen capture
function is provided by, for example, an operating system, or can be
realized by executing screen capture software. Hence, there is a problem
that content such as personal information or copyrighted work which is
undesirable to be replicated is easily replicated.

[0003] Therefore, for example, a method is proposed of restricting
browsing of content without browsers to which a function of disabling
screen capture is added. However, if a user takes a picture of a screen,
it is still possible to replicate display content on the screen.

[0004] With regard to this problem, Patent Literature 1 discloses a
technique of preventing digital shoplifting of capturing an image of
content of a book using a digital camera. More specifically, digital
watermark is printed on pages of a book. Further, when the digital camera
detects digital watermark from captured images, processing of forbidding
storage or transmission of images, or tessellating the captured images or
destroying readability of letters.

[0006] However, the technique disclosed in Patent Literature 1 requires
that a digital camera itself has a function of preventing digital
shoplifting. Hence, replication can be carried out by capturing an image
using a digital camera without this function.

[0007] In light of the above foregoing problems, it is therefore an object
of the present invention to provide a data-generating device, a
data-generating method, a data-generating program and a recording medium
which can prevent content displayed on a screen from being accurately
replicated.

Means for Solving the Problem

[0008] In order to solve the above problem, the invention according to
claim 1 is a data-generating device comprising:

[0009] an acquiring means that acquires still image data;

[0010] a still image data generating means that generates a predetermined
number of items of still image data in which at least part of pixels of
the acquired still image data are masked, and that varies positions of at
least part of pixels in pixels to be masked, between at least two items
of still image data of the predetermined number of still image data; and

[0011] a movie data generating means that generates movie data for which
each of the generated still image data is displayed at a predetermined
frame rate.

[0012] According to the present invention, the generated movie data is
played back, so that a predetermined number of items of still image data
are sequentially displayed at predetermined time intervals. Hence, even
when display content on the screen at a given moment is replicated by
screen capture or image capturing, content to be replicated is only the
same as display content of one still image data of the predetermined
number of items of still image data in which at least part of pixels are
masked. By contrast with this, while the predetermined number of items of
still image data are sequentially displayed at predetermined time
intervals, unmasked pixels of each still image data are displayed on the
screen. Consequently, it is possible to make people who look at the
screen recognize that content more similar to display content of the
acquired original still image data than each one of the predetermined
number of items of still image data is displayed. Consequently, it is
possible to prevent content displayed on the screen from being accurately
replicated.

[0013] The invention according to claim 2 is the data-generating device
according to claim 1,

[0014] wherein the still image data generating means determines a position
of a pixel to be masked such that a mask pattern of still image data to
be generated becomes irregular.

[0015] The invention according to claim 3 is the data-generating device
according to claim 1 or claim 2,

[0016] wherein the still image data generating means varies a rate of
pixels to be masked in at least one of regions divided from an image
shown by at least one still image data of the predetermined number of
items of still image data, from a rate of pixels to be masked in other
regions.

[0017] According to the present invention, there is a region having a
different rate of pixels to be masked from other regions, so that it is
possible to make recognition of display content of the acquired original
still image data difficult.

[0018] The invention according to claim 4 is the data-generating device
according to any one of claims 1 to 3,

[0019] wherein the still image data generating means sets a rate of pixels
to be masked at an outline portion of an image shown by the acquired
still image data to be greater than a rate of pixels to be masked at
other portions.

[0020] According to the present invention, an outline portion of the image
of replicated content becomes vaguer, so that it is possible to make
recognition of display content of the original still image data from the
replicated content difficult.

[0021] The invention according to claim 5 is the data-generating device
according to any one of claims 1 to 4,

[0022] wherein still image data is generated in which at least one pixel
is not masked among pixels of matching display positions between the
predetermined number of items of still image data.

[0023] According to the present invention, at a point of time when all of
the predetermined number of items of still image data are displayed by
playing back the generated movie data, unmasked pixels are displayed at
least once at each display position. Consequently, it is possible to make
people who look at the screen more accurately recognize display content
of the original still image data.

[0024] The invention according to claim 6 is the data-generating device
according to any one of claims 1 to 5,

[0025] wherein the still image data generating means sets a rate of pixels
to be masked higher when a number of items of still image data to
generate is greater.

[0026] According to the present invention, the rate of pixels to be masked
increases, so that it is possible to make recognition of display content
of the acquired original still image data from the replicated content
difficult. Further, even when the number of unmasked pixels per one still
image data configuring movie data decreases, the number of items of still
image data increases, so that it is possible to prevent recognition of
display content of the original still image data from being difficult for
people who look at the screen.

[0027] The invention according to claim 7 is the data-generating device
according to any one of claims 1 to 6,

[0028] wherein the still image data generating means generates still image
data in which a pixel to be masked is painted with a color determined as
a masking color.

[0029] The invention according to claim 8 is the data-generating device
according to claim 7,

[0030] wherein the still image data generating means uses an intermediate
color between a color of a pixel to be masked and a color of pixels
around the pixel as a masking color.

[0031] According to the present invention, a color of the masked pixel is
displayed as an intermediate color of an original color of the pixel and
a color of pixels around this pixel, so that it is possible to make
recognition of display content of the acquired original still image data
from the replicated content difficult.

[0032] The invention according to claim 9 is the data-generating device
according to any one of claims 1 to 8,

[0034] the still image data generating means comprises a generation image
number determining means that determines a number of items of still image
data to generate based on the determined frame rate.

[0035] According to the present invention, it is possible to determine a
number suitable for the frame rate as the number of items of still image
data configuring movie data. Consequently, it is possible to make
adjustment to make recognition of display content on the screen easy for
people who look at the screen.

[0036] The invention according to claim 10 is the data-generating device
according to any one of claims 1 to 9,

[0037] wherein the acquiring means comprises:

[0038] an electronic data acquiring means that acquires electronic data
which can be displayed on a screen of a display device; and

[0039] a converting means that converts the acquired electronic data into
still image data.

[0040] According to the present invention, even when electronic data is
not still image data, it is possible to prevent display content of
electronic data on the screen from being accurately replicated.

[0041] The invention according to claim 11 is a data-generating method
comprising:

[0042] an acquiring step of acquiring still image data;

[0043] a still image data generating step of generating a predetermined
number of items of still image data in which at least part of pixels of
the acquired still image data are masked, and varying positions of at
least part of pixels in pixels to be masked, between at least two items
of still image data of the predetermined number of still image data; and

[0044] a movie data generating step of generating movie data for which
each of the generated still image data is displayed at a predetermined
frame rate.

[0045] The invention according to claim 12 is a data-generating program
causing a computer to function as:

[0046] an acquiring means that acquires still image data;

[0047] a still image data generating means that generates a predetermined
number of items of still image data in which at least part of pixels of
the acquired still image data are masked, and that varies positions of at
least part of pixels in pixels to be masked, between at least two items
of still image data of the predetermined number of still image data; and

[0048] a movie data generating means that generates movie data for which
each of the generated still image data is displayed at a predetermined
frame rate.

[0049] The invention according to claim 13 is a recording medium in which
a data-generating program is computer-readably recorded, the program
causing a computer to function as:

[0050] an acquiring means that acquires still image data;

[0051] a still image data generating means that generates a predetermined
number of items of still image data in which at least part of pixels of
the acquired still image data are masked, and that varies positions of at
least part of pixels in pixels to be masked, between at least two items
of still image data of the predetermined number of still image data; and

[0052] a movie data generating means that generates movie data for which
each of the generated still image data is displayed at a predetermined
frame rate.

Advantageous Effects of Invention

[0053] According to the present invention, the generated movie data is
played back, so that a predetermined number of items of still image data
are sequentially displayed at predetermined time intervals. Hence, even
when display content on the screen at a given moment is replicated by
screen capture and image capturing, content to be replicated is only the
same as display content of one still image data among a predetermined
number of items of still image data in which at least part of pixels are
masked. By contrast with this, while the predetermined number of items of
still image data are sequentially displayed at predetermined time
intervals, unmasked pixels of each still image data are displayed on the
screen. Consequently, it is possible to make people who look at the
screen recognize that content more similar to display content of the
acquired original still image data than each one of the predetermined
number of items of still image data is displayed. Consequently, it is
possible to prevent content displayed on the screen from being accurately
replicated.

BRIEF DESCRIPTION OF DRAWINGS

[0054]FIG. 1 is a block diagram illustrating an example of a schematic
configuration of an electronic data converting device 1 according to an
embodiment.

[0055] FIG. 2 is a view illustrating an example of a screen display image
of electronic data and a screen display image of frame image data
configuring movie data according to one embodiment.

[0056]FIG. 3 is a flowchart illustrating a processing example of a system
control unit 20 of the electronic data converting device 1 according to
one embodiment.

[0058] Hereinafter, an embodiment of the present invention will be
described in details with reference to the drawings. In addition, the
embodiment will be described below where a data-generating device
according to the present invention is applied to an electronic data
converting device.

[0059] [1. Configuration of Electronic Data Converting Device]

[0060] First, a configuration of an electronic data converting device 1
according to the present embodiment will be described using FIG. 1.

[0061]FIG. 1 is a block diagram illustrating an example of a schematic
configuration of an electronic data converting device 1 according to the
present embodiment.

[0062] As illustrated in FIG. 1, the electronic data converting device 1
has an operation unit 11, a display unit 12, a communication unit 13, a
drive unit 14, a memory unit 15, an input/output interface unit 16 and a
system control unit 20. Further, the system control unit 20 and the
input/output interface unit 16 are connected through the system bus 21.

[0063] The operation unit 11 employs a configuration including, for
example, a keyboard and a mouse, and receives an operation command from a
user and outputs content of the command to the system control unit 20 as
a command signal. The display unit 12 is, for example, a computer display
such as a CRT (Cathode Ray Tube) display or a liquid crystal display, and
displays information such as characters and images. The communication
unit 13 connects to a network such as a LAN (Local Area Network) to
control communication states with other information processing devices.
The drive unit 14 reads, for example, data from a disc DK such as a
flexible disc, a CD (Compact Disc) or a DVD (Digital Versatile Disc), and
records, for example, data in the disc DK.

[0064] The memory unit 15 employs a configuration including, for example,
a hard disc drive, and stores, for example, various programs (including
an example of a data-generating program according to the present
invention) and data. The programs stored in the memory unit 15 may be
acquired from, for example, another information processing device through
the network, or may be recorded in the disc DK and read through the drive
unit 14. The input/output interface unit 16 performs interface processing
between the operation unit 11 to the memory unit 15, and the control unit
20. The system control unit 20 is formed with, for example, a CPU
(Central Processing Unit) 17, a ROM (Read Only Memory) 18 and a RAM 19.
When the CPU 17 reads and executes the various programs stored in the ROM
18 or the memory unit 15, the system control unit 20 controls each unit
of the electronic data converting device 1. Further, the system control
unit 20 functions as acquiring means, still image data generating means,
movie data generating means, frame rate determining means, generation
image number determining means, electronic data acquiring means and
converting means according to the present invention.

[0065] For the electronic data converting device, for example, a personal
computer or a server device can be adopted.

[0066] [2. Outline of Function of Electronic Data Converting Device]

[0067] Next, the outline of a function of the electronic data converting
device 1 according to the present embodiment will be described using FIG.
2.

[0068] FIG. 2 is a view illustrating an example of a screen display image
of electronic data and a display image of frame image data configuring
movie data according to the present embodiment.

[0069] The electronic data converting device 1 converts specified
electronic data into movie data. The type of electronic data of a
conversion target is not particularly limited as long as the electronic
data can be displayed on the screen. For example, electronic data of a
conversion target includes, for example, electronic document, image data
and web pages (more specifically, HTML document configuring web pages,
image data, electronic document and text data). In addition, an example
of a screen display image of electronic data illustrated in FIG. 2
illustrates a pattern showing a character "", which is indicated in
black, in a white background.

[0070] More specifically, when people look at a screen of the computer
display which displays a movie by movie data playback processing, the
electronic data converting device 1 generates movie data which allows
people to recognize the same image as the screen display image of
electronic data with their own eyes. Further, even when an action such as
screen capture or image capturing is taken while movie data is displayed
(hereinafter, referred to as "screen replication action"), the electronic
data converting device 1 generates movie data from which the screen
display image of electronic data cannot be accurately replicated.

[0071] More specifically, as illustrated in FIG. 2, movie data configured
with a plurality of items of frame image data is generated from still
image data corresponding to a screen display image of electronic data.
Each frame image data is still image data and, when movie data is played
back, a plurality of items of frame image data configuring movie data are
sequentially displayed on the screen at a predetermined frame rate and
repeatedly displayed. For a format of such movie data, for example, SWF
(Small Web Format) of Adobe Flash (registered trademark) may be adopted.
Meanwhile, the format of movie data is by no means limited to a specific
format.

[0072] Each frame image data configuring movie data is still image data in
which at least part of pixels are masked among pixels configuring the
original still image data corresponding to the screen display image of
each electronic data. Masking of a pixel according to the present
embodiment is directed to painting a pixel of a masking target with some
color (hereinafter "masking color"), and converting the original color of
the pixel of the masking target. More specifically, masking of a pixel is
directed to generating frame image data for which a pixel of a masking
target is displayed with a color determined as a masking color instead of
the original color of the pixel of the masking target. However, in some
cases, a masking color of part of pixels is the same as the original
color of a pixel of a masking target. FIG. 2 illustrates an example where
a masking color is the same white color as a background color, and
illustrates that part of the pattern of "" is defective in a screen
display image of each masked image data. In addition, a method of
determining a masking color will be described below.

[0073] A pattern of the coordinate of a pixel to be masked varies between
each frame image data configuring movie data. Meanwhile, different
patterns of coordinates of pixels to be masked mean that at least part of
coordinates of pixels to be masked, that is, display positions of these
pixels are different. More specifically, the coordinate of a pixel to be
masked is determined at random in one pixel unit. By this means, a
masking pattern does not become the same between each frame image data,
and a masking pattern does not have a regular pattern such as a stripe
pattern. By contrast with this, focusing on an arbitrary coordinate of
frame image data, there is at least one frame image data in which a pixel
is not masked, among all items of frame image data. These conditions are
satisfied between all coordinates. In addition, at part of coordinates,
part of pixels may not be masked in all items of frame image data.

[0074] One of items of frame image data configuring movie data is
displayed on a screen at a given moment when this movie data is played
back. Then, even if a display image of the screen at a given screen is
replicated by a screen replication action, an image to be replicated has
a defect masked portion in frame image data. Consequently, it is not
possible to accurately replicate the screen display image of electronic
data. By contrast with this, at a point of time when all frame images
configuring movie data are displayed, an unmasked pixel is displayed at
least once. Then, it is possible to make people who look at the screen
recognize as if the screen display image of the original electronic data
is displayed due to, for example, an after image effect.

[0075] Next, a method of determining a frame rate, the number of frames
and a masking factor of movie data to generate will be described. The
frame rate, the number of frames and the masking factor may be set by
each user or may be automatically determined by the electronic data
converting device 1, or a value determined in advance as a fixed value
may be stored in the memory unit 15.

[0076] When the frame rate is determined by the electronic data converting
device 1, the system control unit 20 first acquires, for example, an
assumable refresh rate (vertical synchronization frequency) of the
computer display. This refresh rate may be inputted by, for example, the
user. Instead, when the electronic data converting device 1 targets at
playing back movie data, the system control unit 20 may acquire the
setting of a current refresh rate of the display unit 12. Further, the
system control unit 20 determines the frame rate based on the acquired
refresh rate. More specifically, the fresh rate is the same value as or
less than the refresh rate. Further, for example, the frame rate may be
the same value as one of the divisor of the refresh rate. By so doing, it
is possible to prevent an image from flickering when movie data is played
back. However, in some cases, when the frame rate is too low and movie
data is played back, people who look at the screen have difficulty in
recognizing a screen display image of the original electronic data.
Hence, a lower limit value which can be determined as a frame rate may be
set. In this case, the system control unit 20 determines the frame rate
such that the frame rate is a lower limit value or more. When, for
example, the refresh rate is 60 Hz and the lower limit value of the frame
rate is 24 fps, the frame rate is 30 fps or 60 fps.

[0077] The number of frames is the number of items of frame image data
configuring movie data, and is two or more at the minimum requisite. When
the electronic data converting device 1 determines the number of frames,
for example, the system control unit 20 determines the number of frames
based on the frame rate. One of reasons for increasing the number of
frames is to decrease quality of images generated by an image replication
action. As described below, when the number of frames is greater, the
masking factor can be set higher. Further, when the masking factor is
higher, it is more difficult to recognize a screen display image of the
original electronic data from an image generated by a screen replication
action. Meanwhile, when the number of frames is greater and a longer time
is required to display all items of frame image data, recognition of a
screen display image of the original electronic data becomes difficult in
some cases. This is because, when, for example, the number of frames is
increased to increase the masking factor, the ratio of a display time of
unmasked pixels to the time required to display all items of frame image
data is likely to become low. Hence, for example, an upper limit value of
a time required to display all items of frame image data is set in
advance. Further, the system control unit 20 determines the number of
frames such that the time required when all items of frame image data are
sequentially displayed at the determined frame rate is the set upper
limit value or less. In this case, when the frame rate is higher, the
number of frames can be set greater.

[0078] The masking factor refers to the rate of the number of pixels to be
masked with respect to the total number of pixels configuring frame image
data. When the electronic data converting device 1 determines the masking
factor, the system control unit 20 determines the masking factor based on
the number of frames. More specifically, when the number of frames is
greater, the masking factor is set higher. When the masking factor is
higher, it is possible to further decrease quality of an image generated
by a screen replication action. Further, by sufficiently setting a higher
masking factor (for example, 90% or more), it is possible to disable
recognition of display content of the original electronic data from an
image generated by a screen replication action, or make this recognition
difficult. By this means, it is possible to prevent, for example, leakage
of personal information or confidential information due to a screen
replication action, or prevent secondary use of copyrighted work due to a
screen replication action.

[0079] When the user determines the frame rate, the number of frames and
the masking factor, the electronic data converting device 1 may have a
function of adjusting the frame rate, the number of frames and the
masking factor while the user checks a movie displayed on the display
unit 12 by playing back the generated movie data.

[0080] Next, a method of determining a masking color will be described.
There are various methods of determining a masking color.

[0081] For example, a masking color may be an intermediate color of the
original color of a pixel to masked, and a background color around the
pixel to be masked. For example, the system control unit 20 analyzes a
screen display image of electronic data, and specifies, for example, a
foreground portion and a background portion from this display image.
Further, the system control unit 20 acquires colors of pixels in the
background portion in a region of a predetermined number of pixels in a
vertical direction and a horizontal direction around the pixel to be
masked. Still further, the system control unit 20 calculates an average
of brightness values of R (red), G (green) and B (blue) based on the
acquired colors and the color of the pixel to be masked. Meanwhile, the
calculated brightness values are brightness values of masking colors. As
described above, an intermediate color of the original color of the pixel
to be masked and the background colors around the pixel to be masked is
used as a masking color, so that an image generated by a screen
replication action looks blurred. Consequently, it is possible to make
recognition of content of a screen display image of the original
electronic data from the image generated by the screen replication action
more difficult. This is particularly effective when a screen display
image of electronic data is represented by a plurality of hues (multiple
colors). In addition, an intermediate color for a masking color may not
be a color which is not right in the middle of the original color of the
pixel to be masked and a background color around the pixel to be masked.

[0082] Further, for example, the masking color may be an intermediate
color of all pixels in a region of a predetermined number of pixels in
the vertical and horizontal direction around a pixel to be masked.
Furthermore, for example, a masking color may be the same color as a
background color of a screen display image of electronic data. Still
further, a masking color may be a fixed color determined in advance, and
brightness values of R, G and B of this fixed color may be stored in the
memory unit 15. Moreover, the user may determine a masking color.

[0083] [3. Operation of Electronic Data Converting Device]

[0084] Next, the operation of the electronic data converting device 1 will
be described using FIG. 3.

[0085]FIG. 3 is a flowchart illustrating a processing example of the
system control unit 20 of the electronic data converting device 1
according to the present embodiment.

[0086] First, the system control unit 20 functions as acquiring means to
acquire electronic data, and convert the acquired electronic data into
still image data (step S1). More specifically, the system control unit 20
functions as electronic data acquiring means to acquire, for example,
electronic data specified according to a user's operation of the
operation unit 11. In this case, the system control unit 20 may acquire
electronic data from, for example, another information processing device
through the communication unit 13 and the network, may read electronic
data from the disc DK through the drive unit 14 or may acquire electronic
data stored in the memory unit 15. Further, the system control unit 20
functions as converting means to, for example, rasterize the acquired
electronic data, generate still image data and store the still image data
in the memory unit 15 as a data file of a predetermined format. The
format of still image data includes, for example, a JPEG format, a TIFF
format and a BMP format. Further, the system control unit 20 finds the
numbers of pixels of the generated still image data in the vertical and
horizontal directions, and the total number of pixels. In addition, when
the acquired electronic data is still image data, the system control unit
20 can skip conversion processing.

[0087] Next, the system control unit 20 expands a bit map image of the
generated still image data on a predetermined region of the RAM 19 (step
S2). This bit map image is, for example, data adopting an alignment
structure in which brightness values of R, G and B are set according to
each coordinate. This bit map image corresponds to a screen display image
of electronic data. In addition, when electronic data is converted into
still image data, the system control unit 20 can also set still image
data directly in the RAM 19 as a bit map image instead of temporarily
storing still image data as a data file.

[0088] Next, the system control unit 20 functions as still image data
generating means to generate a plurality of items of frame image data in
steps S3 to S17.

[0089] First, the system control unit 20 functions as frame rate
determining means to determine a frame rate of movie data to generate,
based on an assumable refresh rate of the computer display (step S3).
Next, the system control unit 20 functions as generation image number
determining means to determine the number of frames FN of movie data to
generate, based on the determined frame rate (step S4). Next, the system
control unit 20 determines the number of maskings MN (step S5). More
specifically, the system control unit 20 determines the masking factor
based on the number of frames FN. Furthermore, the system control unit 20
multiplies the total number of pixels of still image data with the
determined masking factor to calculate the number of maskings MN. In
addition, the example of the method of determining the frame rate, the
number of frames and the masking factor has already been described, and
therefore will not be described here.

[0090] Next, the system control unit 20 makes nine copies of the expanded
bit map image on the RAM 19 (step S6). Each copied bit map image
corresponds to frame image data. Further, each bit map image is assigned
one of frame numbers 1 to FN.

[0091] Next, the system control unit 20 determines a frame in which a
pixel is not masked, at random for each coordinate of still image data
(step S7). For example, the system control unit 20 generates one of
numbers 1 to FN at random, and stores the generated number in the RAM 19
as a number of a frame in which a pixel of a coordinate of interest is
not masked. The system control unit 20 performs this processing for all
coordinates of still image data.

[0092] Next, the system control unit 20 sets 1 to a variable i indicating
a frame number (step S8). Next, the system control unit 20 determines MN
coordinates at which pixels are masked in a bit map image of the frame i,
at random (step S9). In this case, the system control unit 20 selects a
coordinate other than the coordinates at which pixels are decided not to
be masked in the frame i in step S7. The coordinate at which a pixel is
masked is stored in the RAM 19 as variables Xn and Yn (n=1, 2,
3 . . . and MN).

[0093] Next, the system control unit 20 sets 1 to a variable j indicating
a coordinate number (step S10). Next, the system control unit 20
determines a masking color of a coordinate (Xj,Yj) (step S11).
In addition, the example of the method of determining a masking color has
already been described, and therefore will not be described. Next, the
system control unit 20 masks the pixel at the coordinate
(Xj,Yj) using the determined masking color (step S12). More
specifically, the system control unit 20 determines each brightness value
of the determined masking color in a region corresponding to the
coordinate (Xj,Yj) of the bit map image in the frame i set in
the RAM 19.

[0094] Next, the system control unit 20 adds 1 to the variable j (step
S13), and determines whether or not the variable j is the number of
maskings MN or less (step S14). In this case, when the variable j is the
number of maskings MN or less (step S14; YES), the system control unit 20
proceeds to step S11.

[0095] By contrast with this, when the variable j is greater than the
number of maskings NM (step S14: NO), the system control unit 20 controls
the memory unit 15 to store the bit map image in the frame i as a file of
frame image data of a predetermined format (step S15).

[0096] Next, the system control unit 20 adds 1 to the variable i (step
S16), and determines whether the variable i is the number of frames FN or
less (step S17). In this case, when the variable i is the number of
frames FN (step S17: YES), the system control unit 20 proceeds to step
S9.

[0097] By contrast with this, when the variable i is greater than the
number of frames FN (step S17: NO), the system control unit 20 functions
as movie data generating means to generate movie data (step S18). More
specifically, the system control unit 20 combines each frame image data
of the generated frame 1 to frame FN to generate movie data. In this
case, the system control unit 20 sets the determined frame rate to, for
example, the frame rate setting portion in movie data. In addition, a
configuration may be employed where each of the above frame image data
may be combined in, for example, an ascending order or a descending order
based on the frame number, or may be combined at random without referring
to the frame number. The system control unit 20 finishes processing
illustrated in FIG. 3 when movie data is generated in this way.

[0098] The generated movie data can be played back by an information
processing device which can play back data of a corresponding format.
This information processing device plays back the generated movie data,
so that frame image data included in movie data is sequentially displayed
on the screen at, for example, the frame rate set in the movie data in
combination order of the frame 1, the frame 2 and the frame 3. Further,
after the last frame image data is displayed, the first frame image data
is displayed again.

[0099] As described above, with the present embodiment, the system control
unit 20 acquires still image data which shows a screen display image of
electronic data as a bit map image, and generates a number of items of
frame image data in which at least part of pixels of the acquired still
image data are masked, according to the determined number of frames. In
this case, the system control unit 20 varies a position pattern of a
pixel to be masked, between each frame image data. Further, the system
control unit 20 generates movie data for which the generated frame image
data is displayed at the determined frame rate.

[0100] Consequently, even when a screen display image at a given moment is
replicated due to a screen replication action, the replicated screen
display image is only the same as the screen display image of one frame
image data in which at least part of pixels are masked. By contrast with
this, compared to a case where frame image data is displayed one by one,
it is possible to make people who look at the screen recognize that
content more similar to the original screen display image is displayed.
Consequently, it is possible to prevent content displayed on the screen
from being accurately replicated.

[0101] Further, the system control unit 20 acquires electronic data and
acquires still image data by converting the acquired electronic data, so
that it is possible to more accurately recognize content of a screen
display image of electronic data which can be displayed.

[0102] Furthermore, the system control unit 20 generates frame image data
such that one of pixels of matching coordinates between each frame image
data is not masked, so that people who look at the screen can more
accurately recognize content of the original screen display image.

[0103] Still further, the system control unit 20 may increase the masking
factor which is the rate of pixels to be masked when the number of frames
is greater. In this case, it is possible to make recognition of content
of a screen display image of the original electronic data from a
replicated screen display image difficult, and prevent recognition of
content of the original screen display image from being difficult for
people who look at the screen.

[0104] Further, the system control unit 20 may use an intermediate color
of a color of a pixel to be masked and a color of pixels around the pixel
as a masking color. In this case, it is possible to make recognition of
content of the original screen display image from a replicated screen
display image difficult.

[0105] Further, the system control unit 20 may determine a frame rate of
movie data, and determine the number of frames of movie data based on the
determined frame rate. In this case, it is possible to determine the
number of frames matching the frame rate and, consequently, make
adjustment such that people who look at the screen can easily recognize a
screen display image.

[0106] In addition, with the above embodiment, the coordinate of a pixel
to be masked is determined at random. However, for example, frame image
data masked according to a pattern determined in advance may be
generated. In this case, for example, information about a mask pattern
per frame is stored in the memory unit 15 in advance. Further, the system
control unit 20 masks a pixel in each frame based on the mask pattern
information. Furthermore, a regular pattern may be used for a mask
pattern. FIG. 4A is an example of a screen display image of frame image
data masked according to a mask pattern of a regular pattern. FIG. 4A
illustrates an example where a position pattern of a pixel to be masked
in each frame is varied by using a checkered pattern for a mask pattern
and shifting the position of the checkered pattern in each frame.

[0107] Further, by dividing a screen display image of each frame image
data into a plurality of regions, the masking factor may be determined
per region. Furthermore, the masking factor of at least one region may be
varied from masking factors of the other regions. FIG. 4B illustrates an
example of a screen display image of frame image data where a screen
display image of each frame image data is vertically and horizontally
divided into two and partitioned into four regions, the masking factor of
one of the regions is 100% and the masking factor of the other three
regions is 50%. Thus, there is a region having a different masking factor
from the other regions, so that it is possible to make recognition of
content of a screen display image of the original electronic data from
replicated content difficult. Further, in FIG. 4B, the region in which
the masking factor is 100% includes an upper right portion in the frame
1, a lower right portion in a frame 2 and a lower left portion in the
frame 3. Thus, a region having a different masking factor from the other
regions may sequentially change per frame. In addition, the masking
factor is by no means limited only to 50% or 100%. Further, it is
possible to set 0% of the masking factor for part of regions, and set a
rate greater than 0% of the masking factor for the other regions.
Furthermore, the masking factor may be set per region by the user. In
this case, it is possible to, for example, set a masking factor of a
region replication of which particularly needs to be prevented in a
screen display image of the original data, higher than masking factors of
the other regions.

[0108] Further, the system control unit 20 may extract an outline portion
such as a character or a pattern by image analysis from a screen display
image of each frame image data, and set a masking factor of the outline
portion higher than a masking factor of other portions than the outline
portion. By this means, the outline portion of an image of replicated
content becomes vaguer, so that it is possible to make recognition of a
screen display image of the original electronic data from a replicated
screen display image difficult. In addition, a method of extracting an
outline portion from an image is known, and therefore will not be
described in details.

[0109] Further, with the above embodiment, one of pixels of matching
coordinates between frame image data is not masked. However, if the
number of pixels is smaller than the number of frames, two or more pixels
may not be masked. Further, there may be part of coordinates of pixels
which are all masked in each frame image data. In this case, although,
when people look at the screen in which movie data is played back, part
of pixels look defective, part of pixels may be defective as long as the
degree of defect is not disadvantageous for recognition of content
displayed on the screen.

[0110] Further, with the above embodiment, patterns of coordinates of
pixels to be masked vary between all items of frame image data. However,
patterns only need to be varied between at least two items of frame image
data.